Fruits of spiny and spineless Opuntia ficus indica are about 110-180 grams, range from 12 to 15% total soluble solids (Brix), have a variety of fruit colors, i.e. green, orange, red and purple, and have been grown in many arid regions of the world such as Mexico, Brazil, Chile, Argentina, Spain, Italy, Israel, and South Africa for commercial fruit production (Parish and Felker, 1997). The market use of the fruit is to be consumed fresh after the peel is removed. Mexico is the world center of production with great variation in spines, fruit colors, dates of maturity and Brix (Mondragon and Gonzalez, 1996). While the lime green variety ‘Reyna’ is the leading cactus pear variety in Mexico (Mondragon and Gonzalez, 1994), this variety has long spines that prevent its cultivation in the USA due to objections from harvesting crews. Mondragon and Gonzalez, (1996) have reported fruits of many colors, but they have not provided experimental details on field design, laboratory methods or coefficients of variation for these properties and they do not provide data on firmness of the edible inner portion which Felker et al., (2005) have suggested needs to be greater than 2.2 lb for a good quality fruit. Moreover D'Arrigo Bros data on fruit Brix, firmness, weight, peel thickness, percentage of edible portion on more than 30,000 fruit of existing varieties and progeny of new crosses is not in agreement with Brix values of 15-16 for red or purple colored fruits reported by Mondragon and Gonzalez, (1996). Opuntia fruit data, from refereed journal articles with field and laboratory experimental details and estimates of variation, have been provided by Barbera et al., (1992), Nerd et al., (1991) and Felker et al., (2005).
In 1998, copies of the more than 100 Opuntia clones obtained from Kingsville, Tex. (that were later deposited in the USDA Opuntia germplasm collection in Parlier, Calif.) that represented all of the major types present in Mexico, South Africa, Argentina and Chile. As described below, none of the existing cultivars met the objectives of high pulp firmness (>2.8 lb), high Brix, (>14), thornlessness and purple color in the same plant and therefore hybridizations were conducted to obtain the desired variety. This collection included the Kingsville, Tex. accession 1279 with dark purple flesh, and is similar to the ‘Charola’ described by Mondragon and Gonzalez (1996).
There are extensive plantations of cactus pear for fruit in the Mediterranean, principally Sicily, but also Spain and Israel. Opuntia ficus indica was brought to Spain on one of the first voyages of Christopher Columbus from where it spread to the rest of the Mediterranean region. In the largest commercial production area of the Mediterranean in Sicily, there are 3 varieties, ‘Rossa’ (with red fruit), ‘Gialla’ (with yellow fruit) and ‘Bianca’ (with almost colorless fruit) (Barbera et al., 1992). These three varieties were essentially the same with regard to fruit quality with a maximum Brix of about 13% (Barbera et al., 1992). Nerd et al., (1991) in Israel, found the Brix of the summer ‘Ofer’ variety (which is yellow and similar to the ‘Gialla’ from Sicily) to be 11.8% in the winter and 12.8% in the summer. In Argentinean field trials, Texas A&M Kingsville (TAMUK) accession 1281 (which is very similar to the Italian ‘Rossa’) and TAMUK 1277 and 1320 (which are similar to Italian ‘Gialla’) had Brix values of about 12.6, 12.7 and 13.0 respectively (Felker et al., 2005).
In spite of acceptable fruit sugar concentrations of about 13% in high yielding varieties, such as Italian ‘Rossa’ and ‘Gialla’ types (including 1281, 1277, 1320), these varieties have very low pulp firmness of about 2 lb (versus 4 lb for spiny orange 1287 and green fruited Argentine and Chilean varieties) which lead to poor consumer acceptance in Argentina (Felker et al., 2005). While firmness is the parameter measured, the objectionable quality is that pulps with low firmness value lack structural integrity and may break apart when the peel is separated from the pulp. A pulp firmness of about 2.2 lb has been suggested as the minimum acceptable for cactus fruit (Felker et al., 2005).
In the USA, the only commercial variety, the ‘Andyboy Red’, is similar to the Italian ‘Rossa’ and has a Brix of about 13.5 in the summer crop but maybe as low as 10.5 in the mid winter crop. Perhaps due to the cooler weather of the growing region in the USA, the red fruits do not break apart when peeled, but they are not as firm and juicy as other types. The ‘Andyboy Red’ is also in the low range of pulp firmness of about 2 lb. In the USA, the major demand from consumers is for the red colored fruit, which also has higher antioxidant values than the yellow or green fruits, but is less than the purple ones (Stintzing et al., 2005).
In addition to the published work on the lack of firmness and Brix in red and purple colored fruits, one of us (PF) has visited cactus plantations in South Africa, Italy, Mexico, Chile and Argentina and has not found firm, high Brix purple fruits in any existing germplasm collection.
Due to the attractive dark purple color and the higher antioxidant values of the purple fruit than red, orange and green ones (Stintzing et al., 2005), it would be very useful to have a purple fruit with high Brix and firmness. In Argentine field trials (Felker et al., 2005), the pulp firmness of two purple varieties TX 1279 and TX 1300 were approximately 2 lb and thus below what we believe is a commercial desirable. Also these two varieties had Brix values of 13.0 and 11.9 respectively. There is purple fruit variety of Opuntia ficus- indica in Mexico named ‘V1’ but it is not in commercial production in Mexico, probably as it does not have as high a Brix or is as firm as the green ‘Reyna.’ Occasionally in Mexico, fruits of Opuntia robusta, known as ‘Tapona’ are consumed since they are the first fruits to mature. Data on these fruits show that while they have a moderate Brix, they are much softer than all other commercial varieties and thus not appreciated.
Therefore using the basic crossing technique of Wang et al., (1996), hybrids were made between high firmness, high Brix fruits of other varieties and commercial high producing, low Brix, low firmness purple fruited varieties to develop a high Brix, high firmness purple fruit with a good commercial yield. Progeny of various crosses were planted near Chualar, Calif. and evaluated for Brix and firmness using previously described techniques (Felker et al., 2005). About one dozen clones of each color class (green, orange, red and purple) from more than 3000 progeny of various crosses were selected and planted in a randomized complete block trial with four replicates (with one plant per replicate) to directly compare fruit characters for these advanced selections. For two years, several fruits were taken from each of the four replicates, once a month from about September till May. The best purple fruited variety of this randomized complete block trial, originally from Block 1, row 21 plant 27 of this trial was found to have the best overall combination of characters and is the subject of this patent. The parents of this plant were a spineless purple fruited accession R7-54:1-01-22 and a spineless green fruited plant R7:53YT:1-01-05 from our germplasm collection. None of the parents have been patented or have patent pending.
Asexual propagation
All cactus pear varieties are asexually propagated by cutting an approximate one year old cladode from the mother plant, allowing the cut scar to heal over for approximately 2 weeks and then planting this unrooted cladode (botanically a portion of a dicot stem) about ⅓ of its height into dry soil. If the cladodes do not rot, 100% of them will root in less than a month without any hormone treatments.
Apomixis, that is the asexual reproductive process that occurs in the ovule of flowering plants, frequently occurs in Opuntia ficus indica (Mondragon-Jacobo, 2001). While the ratio of apomictic seedlings to seedlings resulting from fertilization varies greatly among female parents, we have found that apomixis occurs in this new variety. Thus this variety could be propagated asexually from apomictic seedlings. It is envisioned that this variety could be genetically engineered to include other traits.
This variety is asexually propagated by planting unrooted cladodes. The claimed plant retains its distinctive characteristics and reproduces true to type in successive generations.